Manchester United manager Sir Alex Ferguson expects John O'Shea to miss the remainder of the season following complications after the defender suffered a dead leg.

The injury is more severe than first expected after O'Shea experienced discomfort in the Republic of Ireland's World Cup play-off defeat by France in November.

Ferguson told the Irish Independent: "He's got a terrible injury at the moment. It's one of those sorts of injuries that are unusual. It's like a dead leg except a dead leg is usually only three or four days.

"The problem is that the blood clot became all knotted and when it gets knotted you get calcification so therefore it's a long process to clear that up and he'll probably miss the season now.

"It's a bad blow for the boy and for the team because he can play anywhere."

O'Shea, 28, has shown his adaptability at Old Trafford by playing across the back four as well as in midfield.

Ferguson admits O'Shea would have been a regular in the team given the way his defence has been decimated by injuries this season.

"When you look at all the problems I've had with the back four, he could have played every single one," said the United boss.

O'Shea will also miss Ireland's friendly with Brazil at the Emirates Stadium on March 2 and a scheduled end-of-season training camp.

Ferguson says the upcoming friendly date is one that club managers could do without.

He added: "I don't even think the international managers think they're all that important now. They never play their full team and there's always drop outs."